This invention relates to tube feeders, and more particularly, to an apparatus and method for incrementally feeding tubing along a linear path to a point of use, such as a tube cut-off.
Tube feeders, such as pinch roll feeders, are well known for use in systems making a stationary cut-off of a length of tubing. Such stationary cut-off systems are used to cut a length of tubing into a number of tube pieces with lengths and accuracies that cannot be attained using xe2x80x9cflying cut-offxe2x80x9d systems in-line with a tube mill.
Commonly, the tube pieces are cut to a length that is controlled by a positive stop which engages the length of tubing to suspend the feeding action of the tube feeder while each tube piece is cut from the length of tubing. If tube pieces of different lengths are desired, the stationary cut-off system must be stopped and the positive stop repositioned to provide the new length.
It is also common for conventional feeders to feed one length of tubing at a time into the stationary tube cut-off. This can create a significant amount of scrap as the trailing end of a length of tubing may have to be discarded if it cannot be accurately fed into the stationary cut-off.
In accordance with the present invention, a feeder system is provided for incrementally feeding a tube along a linear tube path to a point of use. The feeder system includes a frame, and first and second belts on the frame. The first and second belts are capable of moving incrementally in respective first and second belt paths and thereby incrementally moving a tube engaged by the first and second belts in the linear tube path.
In one form, the feed system also includes an encoder that is capable of: a) engaging a tube moving in the tube path to measure each distance a tube engaged by the first and second belts moves with each incremental movement of the first and second belts, and b) producing signals indicative of each distance. The signals can be used to control the incremental movements of at least one of the first and second belts.
In one form, the feeder system further includes a servo drive capable of driving at least one of the first and second belts in incremental movements in the respective first and second belt paths, and a controller operably connected to a) the encoder to receive signals therefrom, and b) the servo drive to control the incremental movements of the at least one of the first and second belts by the servo drive in response to the signals received from the encoder.
In one form, there is a tube entry where a tube in the tube path engages the belts and a tube exit where a tube moved by the belts in the tube path disengages from the belts. The encoder is located adjacent the tube exit. A second encoder is provided adjacent the tube entry and is capable of engaging a tube moving in the tube path to measure each distance a tube engaged by the first and second belts moves with each incremental movement of the first and second belts. The second encoder is capable of producing second signals indicative of each distance and which can be used to control movements of at least one of the first and second belts.
In one embodiment, respective first and second portions of the first and second belt paths extend parallel to the linear tube path with the linear tube path extending between the first and second portions of the belt paths. The first portion is fixed relative to the linear tube path. The second portion is movable in a direction away from the linear tube path and the first portion.
In one form, the direction is a generally downward direction.
In one form, the second belt is mounted to the frame for translation of the second portion in the direction.
In one embodiment of the invention, respective first and second portions of the first and second belt paths extend parallel to the linear tube path, with the linear tube path extending between the first and second portions of the belt paths from a tube entry to a tube exit. The first and second belts are mounted to the frame for movement of the first and second belt portions relative to each other between a first position where a tube in a linear path is engaged by the first and second belts for incremental movement therewith, and a second position where a tube in the linear tube path is not engaged by the first and second belts for incremental movement therewith. The feeder system further includes a guide clamp located between the tube exit and the point of use. The clamp includes tube gripper plates movable between a first state wherein a tube in the linear tube path is not engaged by the gripper plates, and a second state wherein a tube in a linear tube path is a) held by the gripper plates with the first and second portions in the second position, and b) guided by the gripper plates along the linear tube path with the first and second portions in the first position.
In one form, the feeder system further includes a controller operably connected to a) at least one of the first and second belts to control movement of the first and second portions between the first and second positions, and b) the guide clamp to control movement of the gripper plates between the first and second states.
In one form, the feeder system further includes a sensor capable of detecting an end of a tube in the linear tube path and producing a signal to the controller indicative of the detected end. As a result of the signal to the controller, the gripper plate moves from the first state to the second state and the first and second portions move from the first position to the second position.
In one form, the feeder system further includes first and second encoders capable of engaging a tube moving in the tube path to measure each distance a tube engaged by the first and second belts moves with each incremental movement of the first and second belts. The encoders are capable of producing signals indicative of each distance, which signals can be used to control the incremental movement of at least one of the first and second belts. The first encoder is located adjacent the tube exit. The second encoder is located adjacent the tube entry.
In accordance with another aspect of the present invention, a method is provided for incrementally feeding a tube along a linear tube path to a point of use. In one form, the method includes the steps of engaging a tube in a linear tube path between first and second movable belts, moving at least one of the belts incrementally to move the tube incrementally along the tube path toward the point of use, measuring the distance the tube travels during the moving step, and controlling the incremental movements of the moving step based on the distance measured in the measuring step.
In one form, the moving step includes moving the first and second belts in respective first and second belt paths extending parallel to the tube path.
In one form, the method includes the steps of simultaneously engaging a leading tube and a trailing tube in a linear tube path between first and second belts, moving at least one of the first and second belts incrementally to move the leading and trailing tubes incrementally along the tube path towards a point of use, and after the leading tube has disengaged from the first and second belts, pushing the leading tube with the trailing tube as the trailing tube is incrementally moved along the tube path by the first and second belts.
In one form, the method further includes the step of guiding the leading tube in the tube path at a location between the point of use and the first and second belts as the leading tube is pushed by the trailing tube.
In one form, the method includes the steps of engaging a tube in a linear tube path between first and second lengths of belt moving incrementally in respective first and second belt paths, and maintaining the position of the first belt path relative to the linear tube path as the second belt path is moved away from the linear tube path and the first belt path.